I had a large bather load yesterday. Before the swim, I brought FC from 8.5 to 9. I added another 25oz afterwards to raise it another 1ppm per pool math. This morning I noticed it was cloudy and smelled funny, don't know if was ammonia or not. FC was at 7.5. I just checked CYA and it was at 50, checked it twice. Last 2 checks were steady at 70, last one 4 days ago. FC now at 6.5. Any thoughts?